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Cylindrical vector beams (CVBs) with unique spatial polarization states have attracted great interest in recent years. However, the generation of high-power CVBs faces a significant challenge due to the limited output power of a single laser. Here, we capitalize on the brightness enhancement offered by coherent beam combining (CBC) technique and propose an architecture for generating arbitrary CVBs based on a CBC system. The phase noise is effectively compensated using an all-fiber internal phase-locking technique. By designing the polarization direction of each beamlet in the laser array, the desired mode of CVB can be generated. This work could provide a reference for generating high-power CVBs. [ABSTRACT FROM AUTHOR]

Perfect vortex beams (PVBs) possess the advantage of a stable light field distribution regardless of their topological charges, and thus they are extensively utilized in various applications, such as free-space optical communication, optical tweezers and laser processing. Herein, we report a new strategy to generate and modulate PVBs using coherent beam combining (CBC) technology. Both piston phase and tilting phase controlling methods have been successfully employed, and the corresponding properties of the generated PVBs have been fully investigated. Moreover, the number and position of the gaps in fractional perfect vortex beams (FPVBs) could be precisely controlled, and the relationships between these modulated parameters and the performance of FPVBs are uncovered. These simulation analysis results demonstrate the potential for flexible modulation of PVBs or FPVBs in the CBC system, indicating promising prospects for coherent beam arrays (CBAs) in laser beam shaping and achieving high-power structured light. [ABSTRACT FROM AUTHOR]

Leaf is the main organ of photosynthesis. Leaf phenotypic plasticity largely determines the adaptation of plants to enriched nitrogen (N) environments. However, it remains unclear whether the optimal number (proportion) of leaves representing the leaf traits of the whole plant is similar between ambient and N-enriched conditions. Moreover, whether alteration in ammonium (NH4+-N) to nitrate (NO3−-N) ratios in atmospheric N deposition will alter the optimal leaf number is unexplored. By adding three NH4+-N/NO3−-N ratios in a temperate grassland of northern China since 2014, three traits (leaf area, thickness and chlorophyll content) of two dominant clonal grasses, Leymus chinensis and Agropyron cristatum , were measured in August 2020. Results showed that under ambient conditions, the mean leaf area, thickness and chlorophyll content values of two fully expanded leaves were similar to these of all leaves at the plant level, except for the leaf area of L. chinensis , which needed five leaves (78.82% of leaves in the plant). The ratios of NH4+-N/NO3−-N increased the number of required sampled leaves and significantly changed the mean value of leaf traits and the maximum value along leaf order. Moreover, the ratios of NH4+-N/NO3−-N altered the trade-off among the three leaf traits, which is dependent on leaf order, by increasing leaf area and decreasing leaf thickness. Therefore, our study suggests that to better indicate the leaf traits' value of the whole plant under N-enriched conditions, measuring all fully expanded leaves or providing a suitable scaling-up parameter is needed. [ABSTRACT FROM AUTHOR]

Thermal pollution resulting from the release of ventilation air methane (VAM) has emerged as a pressing concern in coal mining. This study aims to address this issue by harnessing the waste VAM energy and converting it into reusable resources, employing an efficient thermal flow reversal reactor. The research investigates five distinct heat extraction strategies and compares their performance. The numerical analysis focuses on transient heat recovery performance by employing a two-step reaction mechanism. Furthermore, the study uncovers the heat transfer characteristics of heat exchange tubes and conducts an analysis of construction costs and profit periods for the different strategies. The findings indicate that the central heat recovery strategy exhibits inferior recovery performance, resulting in higher outlet temperatures and lower extracted power. Conversely, the end recovery strategy successfully reduces heat loss by 56%. The two-sided strategy demonstrates better recovery performance, maintaining an average outlet temperature of 311 K. Additionally, the heat recovery efficiency of the heat exchange tube is approximately 85.6%. Although the combination strategy appears to reduce outlet heat loss, it results in an extended investment payback period. [ABSTRACT FROM AUTHOR]

Background As a traditional Chinese therapy, acupuncture is proposed worldwide as a treatment for pain and other health problems, but findings on acupuncture analgesia have been inconsistent because of its variable modalities of therapeutic intervention. Objective This study aimed to evaluate the existing animal studies for evidence on acupuncture and its effect on glia in association with a reduction in pain conditions. Methods Literature searches were performed in four English- and Chinese-language databases (Web of Science, PubMed, EMBASE, and CNKI) on October 8, 2021. Included studies reported the pain outcome (e.g. paw withdrawal latency, paw withdrawal threshold) and glia outcome (e.g. glial marker GFPA, Iba1, and OX42) in pain-induced animals during acupuncture treatment. Results Fifty-two preclinical studies were included in the meta-analysis. A single acupuncture treatment in rodents had an analgesic effect, which was more effective in inflammatory pain than in neuropathic pain in the early phase of treatment. The analgesic efficacy became more curative after repeated acupuncture. Furthermore, acupuncture treatment could effectively inhibit the activity of astrocytes and microglia in both inflammatory pain and neuropathic pain in a time-course pattern. Conclusions Acupuncture treatment improves analgesic effect in rodent pain conditions under the possible mechanism of glial inhibition. Therefore, these results provide an opportunity to evaluate the effectiveness of acupuncture analgesia and neuroinflammation in animal models to research further neurobiological mechanisms and to inform the design of future clinical trials. Study registration PROSPERO (ID: CRD42020196011). [ABSTRACT FROM AUTHOR]